Electric thermostat



(No Model.)

- T. REEVE.

ELECTRIC THERMOSTAT.

Patented Jan. 2,1883.

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UNITED STATES PATENT OFFICE.

THOMAS REEVE, OF BROOKLYN, N. Y., ASSIG-NOR TO THE YVATKINS AUTO- MATIC SIGNAL TELEGRAPH COMPANY, (LIMITED,) OF NINV- YORK.

ELECTRIC TH ERMOSTAT.

SPECIFICATION forming part of Letters Patent No. 269,960, dated January 2, 1883,

Application riled July 31, 1882. (No model.)

To all whom it may concern Be it known that I, THOMAS REEVE, a citl' zen of the United States, residing atBrooklyn, in the county of Kings and State of New York,

have invented new and useful Improvements in Electric Thermostats, of which the following is a specification.

This invention relates to-that class of thermostats wherein a compound narrow strip of different metals is bent into a convolute or spiral secured at its center by a screw, and having. its free end arranged adjacent to an insulated contact-point, so that by the expansion of the compound stripits free end touches the 1 contact-point, and thereby completes an electric circuit through the thermostat.

The objects of my invention are to provide novel means for holding the contact point or pin insulated from the metallic base-plate of the instrument and in proper position to be touched by thefree end of the compound metal strip, and to provide novel means for firmly connecting-the stationaryend of the strip with the metallic base-plate to insure the certain 2 contact of the free end of said strip with the contact point or pin when expanded, and thus provide correct action of the thermostat under all conditions.

The objects of my invention 1 accomplish by the devices illustrated in'the accompanying drawings, in which-- Figure 1 represents a section in the plane 00 :r, Fig. 2. Fig. 2 is a section in the plane y y, Fig. 1. Fig. 3 is a detached section of the but-- 5 ton supporting the compound strip;

Similar letters indicate corresponding parts.

In the drawings, the letter A designates the case which incloses the working parts of my thermostat, and which is composed of a base- 0 plate, a, and a bell-shaped cover, b. Any other form of case, may, however, be used. Do the metallic base-plate of my case is firmly secured the compound strip B, which consists of a strip of iron or steel and a strip of brass, (or any 5 other suitable metals,) the two strips being firmly united by soldering or brazing. Of these metal strips, that which possesses the most expansibility is the one of brass, and it is arranged outside the iron or steel strip. Thecompound strip B is bentin theform ot'aconvolute curve, and its inner end, 0, which is reduced in width, as shown in Fig. 1, is placed into a groove, (1, formed in a button, 0, and firmly secured therein by brazing or otherwise. The button 0 is made of metal, and is fastened to the metallic r: base-plate a by ascrew, d,which passesthrough a central perforation in the button and enters the base-plate. The free end of the convolute compound strip B is provided. with a tip, c,of platinum, and it is situated in close proximity to a pin or screw, 0, the point of which is also tipped with platinum. This pin is secured in a screw, j, which is insulated from the baseplate a of the case by a porcelain disk, 9, on the inside and a flanged porcelain nipple, h, on the outside. From the screw f extends a metallic plate, t, to a screw,j, which extends through the base-plate a, and is insulated from the same in the same manner as the screw j. Nuts It I insure the metallic contact between the plate 1' and the screws f j. The screw j forms a clamping-screw, which connects by a wire, 10, with one pole of an electric battery. In the hase-plate a is also secured a clampingscrew,m, which is in metallic contact with the base-plate. When the convolute compound strip B expands by heat its tip comes in contact with the point of the pin a, and the circuit of the battery is closed.

By the provision of the screw f, insulated from the base-plate, and havingits head transversely perforated to receive and hold the contact pin or screw 0, said pin or screw is held in proper position relative to the free end of the compound strip, and by means of the compound strip secured in a side groovcin the centrallyperforated button 0, through which perforation passes the screw d to secure it to the baseplate. The said strip is secured in a simple and substantial manner to the base-plate,and the metallic contact between the inner end of the strip and the base-plate is insured, while the correct action of the thermostat is rendered positive and certain in a simple and eflicient manner.

I do not claim as my invention the-compound strip, such having been used in thermostats for a long time.

What I claim as new, and desire to secure by Letters Patent, is

l. In a thermostat, the combination, with the metallic base-plate a and the convolute compound strip B, rigidly connected at one end with the base-plate and free at the other end, of the'screw f, secured tobut insulated from the base-plate, and having a transverse perforation in its head, within which is secured the horizontal contact pin or screw e,substantially as described.

2. In a thermostat, the combination, with the metallic base-plate and the eonvolute compound strip B, rigidly connected at one end with the base-plate and free at the other end, of the screw f, connected with the base-plate by an insulated disk, g, and carrying at its head the horizontal contact pin or screw e, the metallic plate t attached at one end to the said screw, and the screw j, connected with the other end of the metallic plate and with the base-plate by an insulating-disk,substantially as described.

3. In a thermostat, the combination of the base-plate a, the centrally-perforated button 0, having the side groove, 1, the screw (I,passing through the perforation in the button into the base-plate, and the compound metal strip having one end fixed in the side groove of the but ton, substantially as described.

4. In a thermostat, the combination of the metallic base-plate a, the screw f, connected therewith by an insulating-disk,g, and having its head provided with the horizontal contact pin or serewc, the centrally-perforated button G, having a side groove, I, the screw (1, passing through the [)GifOltttlOll in the button into the base-plate, and the convolnte compound strip B, having one end secured to the side groove in the button, substantially as described.

In testimony whereofl have hereunto set my hand and seal in the presence of two subscribing witnesses.

THUS. HERVE. it. Witnesses W. HAUFF, O'r'ro HUFELAND, 

